High-G event detection is supported on our battery powered devices. High-G events can be enabled in the Accelerometer Settings tab on OEM server:
|Oyster||1.6 and above|
|Remora||1.35 and above|
Multi-Axis option available in 2.21/3.21+
Multi-Axis option available in 1.6+
Hard-wired devices support similar features, however the implementation and set up is a bit different, see:
- Accelerometer Event Detection - Accident, Rollover, Tilt, Tip and Rotation Counting
- Accident Detection and Reconstruction
- Harsh Event Setup
Because High-G detection requires the accelerometer to run at a higher speed than usual (100 Hz, versus the usual 12.5 Hz), it is disabled by default. This saves a small amount of battery.
The table below outlines the battery consumption purely from running the accelerometer at a higher speed when High-G events are enabled. Note High-G events may trigger extra fixes and uploads so this will also increase the battery drain. So factor this in when estimating battery life on the Yabbies. The Oyster2 and Remora2 battery meters should track this consumption and report correctly in the percentage.
|State||Current||3 x AAA Lithium Battery/ Year|
(Yabby GPS + Wi-Fi)
|3 x AA Lithium Battery/ Year |
|2 x D Cell LTC Battery/Year|
(Periodic Only tracking, High-G events disabled)
|0 uA||0 %||0%||0%|
|Accelerometer On @ 12.5 Hz|
(Normal tracking, High-G events disabled)
|6 uA||4.5 %||1.75%||0.38%|
|Accelerometer On @ 100 Hz|
(High-G events enabled)
|24 uA||17 %||7%||1.5%|
When enabled, the accelerometer will detect High-G events exceeding the specified force and duration, and log a record containing:
- Log reason 'High-G Event' (46)
- The current time (record time)
- The last known GPS time and position (field 0)
- The peak force seen (FID 24)
- The average force seen (FID 24)
- The duration of the event (FID 24)
Since the immediate record contains only the last known GPS position, the High-G Event Action can be configured to attempt a GPS fix after each High-G event. It can also be told to attempt to upload the result of the fix once, or to continue retrying the fix/upload until they succeed, with increasing back-off timeouts in the event of failure.
In addition to requiring additional battery power for the accelerometer, High-G events use battery when responding to each event. The device must wake up whenever it sees a large force, and verify that the force meets the criteria for logging.
Because the accelerometer is sensitive to gravity, it wakes up more easily when experiencing vertical forces. However, gravity is not considered when evaluating the criteria for logging. This filters out nuisance events from speed bumps, but might in extreme circumstances allow many High-G event wake-ups to go unnoticed, as they did not lead to a logged event.
When using High-G detection in situations prone to repetitive vertical forces (for instance, on corrugated roads, or with continually vibrating machinery) be sure to set the force threshold high enough to avoid repetitive wake-ups, and the associated battery use.
The default threshold of 2Gs is suitable for regular vehicle tracking, where continuous vertical forces are not expected. To determine the minimum safe threshold in challenging environments:
- Set the High-G Event Force threshold to its minimum value (1.5 G @ 10 ms)
- Test the device in its intended application
- If the detector doesn't go off, a threshold of at least 2.6 G is safe
- If it does go off repeatedly, add at least 1.1 G to the reported peak force
High G Alerts
See how to set up an alert step by step here.
As usual, ensure to give the alert a Name and message in the General Tab. Apply it to the relevant assets in the Assets Tab, and select who we should send the alert to under Notifications. Then the other specifics for this feature are:
In the Conditions tab, select 'Use Device Data log Reason' and select High G Event from the list that's populated.
The Asset Timeline history view, will show a history of these alerts.
High G Event Report
In Reports > All Reports, you can select the High G Event Report- Detail or Summary to view the occurrences of the High G Events with a variety of filters including Assets, Asset Types, drivers with the date range as a parameter.
Peak-G, Average-G and Duration
In Telematics Guru, these values are reported in the following Analogue Fields:
- Analogue 18:
- Peak G-Force
- Analogue 19:
- Average G-Force
- Analogue 20:
- Duration of the event
They can be viewed in the device telemetry Assets -> Telemetry
Multi-Axis High-G Event (Remora2 and Remora3)
Multi-Axis High-G event detection logs additional event telemetry per axis. These values are stored in analogues 12 through to 17. This feature is specific to the Remora2 and Remora3
Multi-Axis High-G Event Report
In Reports > All Reports, you can select the Multi-Axis High-G Event Report to view the occurrences of the High-G Events with the Peak and Average G-Force in the X, Y and Z axis